This invention relates to a process for preparing cyclopentenone derivatives.
The compounds contemplated by the invention are cyclopentenone derivatives represented by the formula: ##STR2## wherein R.sub.1 is methyl or ethyl, and R.sub.2 is hydrogen, methyl or acetyl. The cyclopentenone derivatives of this invention are known and are very useful in giving enhanced flavors to foods, beverages, livestock feed, etc.
The cyclopentenone derivatives are heretofore produced by various processes which generally require many and complex steps, give isomers that are difficult to separate, or necessitate the use of hazardous chemicals entailing environmental problems.
For example, J. Org. Chem. 35, 3203 (1970) discloses one of the processes. With this process, the reaction proceeds as follows: ##STR3##
However, this process has various drawbacks, such as low yields (50 to 60%), the use of expensive starting materials and of hazardous and harmful chemicals such as metal sodium and similar highly basic substances, chlorine gas, etc.
An object of this invention is to provide a simplified process for preparing cyclopentenone derivatives.
Another object of this invention is to provide a process for preparing cyclopentenone derivatives in good yields.
Another object of this invention is to provide a process for preparing cyclopentenone derivatives without using hazardous chemicals and, therefore, free of environmental problems.
These and other objects of this invention will become apparent from the following description.